1. Field of the Invention
The invention is directed to the field of subsurface trenching for the installation and removal of various utility items such as electrical cable, conduit, water pipes; sewer pipes and the like where same must be mounted below surface for their protection from the environment and populace and to hide their otherwise unsightly appearance.
2. Description of the Prior Art
The usual method for the laying or removal of utility items such as electrical cables, conduit, water pipes, sewer pipes and the like is to cut or dig a straight sidewall trench of the appropriate depth, lay the cable, conduit or pipe at the trench bottom and cover it up with the soil removed during the trench formation.
When the land is a undeveloped, that is has no structures, plantings, parking lot, etc., upon it, it is a simple matter to cut or dig the trench using mechanized equipment such as trenchers, front loaders, bulldozers or the like, or, if desirable, to manually dig the trench.
However, when the land has been improved as by the building of structures upon the land surface or the surface has been covered as in a parking lot or where gardens and plantings have been placed on the land, installation, removal and/or replacement of utility items is both slow and expensive. Often, space and access limitations prevent any methods other than manual trenching from being used and a in addition to the work itself, there is the disruption of land use and the expense of restoring the trenched area to its former appearance.
In an effort to minimize surface disruption and minimize the costs of surface reconstruction, it has been suggested that a device be constructed to burrow beneath the surface of land and create a bore into which cable, conduit, pipe or the like could be inserted without disturbing the surface of the land or those structures or details thereon. A first type of device was created to permit the replacement of electrical cables and used those cables to guide their movement through the soil which was removed by means of one or more fluid jets. The old cable was pulled from the bore and a new one inserted. A tool of this type is shown in U.S. Pat. Nos. 4,385,667 issued May 31, 1983 and in 4,403,667 issued Sept. 13, 1983.
Although this type of device works well for previously installed electrical cable replacement, it is not suitable for new cable installation because there is no cable to follow and thus no means to independently guide the tool.
U.S. Pat. No. 4,306,627 issued Dec. 22, 1981 shows and describes a tool which can be used for a new installation. A rotating fluid jet drilling nozzle is advanced by a pipe string in much the same manner as a rock drill is employed to dig oil or gas wells. Despite mechanisms to control the position of the nozzle, as is shown in U.S. Pat. No. 4,674,579 issued June 23, 1987, it is still difficult to steer the boring head mounted at the end of a generally rigid pipe string required to push and advance the boring head.
The use of a totally independent tool such as shown in U.S. Pat. No. 3,326,008 issued June 20, 1967 presents different problems. Because it must rely upon only its own drilling head, it is limited as to how fast it can advance and the type of subsoil it can burrow through. Also, since it carries internally the cable it lays, it is limited in its utility. Also, its inability to reverse and retrace the bore it makes limits its ability to draw new cable, conduit or pipe back through the bore. The device must always exit the soil to be recovered and used again.
3. Summary of the Invention
The instant invention overcomes the difficulties noted above with respect to prior art devices for installing, removing and/or replacing existing utility items by providing a fluid-operated self-propelled subsoil penetrating tool of the type including an elongated housing member having a penetrating nose portion capable of ejecting a jet of liquid under high pressure to break up and disrupt the subsoil adjacent such nose portion followed by a two-component hammering of such soil to displace and compact the subsoil as the tool advances. Remotely-operated steering mechanisms control the path of the tool while remotely-read instruments denote the position, depth, direction and attitude of the tool. A trailing umbilical cord provides all motive and operational fluids and electrical power while transmitting instructions and data between the tool and the remote control station. A unique internal structure of two counter-rotating rings of fiberglass rods and a central steel cable reduces the rotation of the tool as it advances and allows for the reverse directional movement of the tool and utility items through the bore created by the movement of the tool through the subsoil.
Interchangeable nozzles may be placed on the nose portion in accordance with the type of subsoil through which the nose is progressing, to get maximum subsoil breakup and disruption. The usual front burrowing nose portion can be replaced with a back reamer to operate the tool in the reverse direction back along the bore while enlarging the diameter of same.
Using a combination of mercury switches with remote read-out and two trim tab indicators, the orientation, azimuth attitude and depth of the penetrating nose can be determined and the azimuth confirmed by means of an external cable locater positioned above and ground above the submerged nose portion. Signals fed from the control panels in response to the operation of joy stick controllers guide the nose portion to avoid obstructions in the subsoil and cause the nose portion to traverse the desired path. A rotatable panel on the control panel accounts for changes in orientation or rotation of the nose portion and alters the meanings of the joy stick controls to insure that the nose portion follows the desired path.
The feed reel for the umbilical cord carries a separate reel to pre-tension the core steel cable and is itself mounted upon a carriage to measure the tension applied to the umbilical cord as it is withdrawn from the bore. It is an object of this invention to provide a fluid-operated self-propelled subsoil penetrating tool.
It is another object of the invention to provide a fluid-operated self-propelled subsoil penetration tool which employs a fluid jet and fluid-propelled hammering to create a bore and propel the tool along such bore.
It is another object of the invention to provide a fluid-operated self-propelled subsoil penetration tool which employs fluid-propelled hammering to propel the tool back along a previously made bore while enlarging same.
It is still another object of the invention to provide a fluid-operated self-propelled subsoil penetration tool which employs a fluid jet and fluid-propelled hammering to create a bore and propel the tool along such bore and which further employs fluid-propelled hammering to propel the tool back along a previously made bore while enlarging same.
It is another object of the invention to provide a remotely-operated steering mechanism for a fluid-operated self-propelled subsoil penetration tool.
It is still another object of the invention to provide a remotely-read display which describes the orientation, azimuth and attitude of a fluid-operated self-propelled subsoil penetration tool.
It is still another object of the invention to provide a remotely-read display which describes the orientation, azimuth and attitude of a fluid-operated self-propelled subsoil penetration tool and a control panel changeable in response to the orientation to delimit the functioning of a remotely-operated steering mechanism to permit the tool to be correctly steered along a desired path.
It is yet another object of the invention to provide a display at a remote read-out point consisting of a series of lamps each operated by a mercury switch located upon a fluid-operated self-propelled subsoil penetration tool to indicate the orientation of the tool with respect to an initial reference.
It is still another object of the invention to provide a combination of an above-surface detector and remotely-indicating means to determine the depth, orientation, azimuth and attitude of a fluid-operated self-propelled subsoil penetration tool.
It is yet another object of the invention to provide a service cable containing all fluid and hydraulic lines and electrical conductors needed for the operation of a self-propelled subsoil penetration tool which substantially prevents rotation of said tool as it advances.
It is still another object of the invention to provide a self-propelled subsoil penetration tool service cable using a belt of fiberglass rods which substantially prevents rotation of said tool as it advances.
It is another object of the invention to provide a self-propelled subsoil penetration tool service cable which substantially prevents rotation of said tool as it advances by using two concentric counter-wound belts of fiberglass rods.
Yet another object of the invention is to provide a self-propelled subsoil penetration tool service cable which substantially prevents rotation of said tool as it advances by using two concentric, counter-wound belts of fiberglass rods and a central steel wire.
Still another object of the invention is to provide a self-propelled subsoil penetration tool service cable which substantially prevents rotation of said tool as it advances by using two concentric, counter-wound belts of fiberglass rods and a pre-tensioned central steel wire.
It is an object of the invention to provide a reeling device for the service cable of a self-propelled subsoil penetration tool which controls the tension in such cable as it is wound upon such reeling device.
It is yet another object of the invention to provide a reeling device for the service cable of a self-propelled subsoil penetration tool which controls the tension in such cable as it is wound upon such reeling device and further includes a complementary reeling device to pretension the steel wire in the service cable during both the reeling and unreeling of the service cable.
Other objects and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principles of the invention and the best modes which have been contemplated for carrying them out.